1. Field of the Invention
This invention relates to a dewatering press, i.e. a machine for compressing materials mixed with or having liquids absorbed therein to remove liquids therefrom.
2. Description of the Prior Art
The paper industry has a problem in the disposal of pulper rejects where the primary feed stock is waste papers. Such rejects may include fiber, plastics, metals, cloth, rubber, etc. but mostly water from the screening process which contributes most of the weight of such rejects. The disposal of such heavy rejects or waste is costly not only in transportation but also, particularly in populous areas, where depositing or "tipping" fees at landfills are high and assessed by weight. Similar problems exist in the transportation and handling of biomass fuels which have a high liquid content.
Nevertheless, there are prior art devices known for removing water from waste products. For example, Tezuka shows in U.S. Pat. No. 3,451,190 a refuse disposal device having feeding and compression boxes. However, only the bottoms of the boxes are provided with drainage holes for the water, thus leaving large amounts of water in the refuse.
Another example of the prior art is known from Bunger who discloses a moisture reducing ram press in U.S. Pat. No. 4,467,715. In the press of Bunger, horizontally extending drainage grooves are arranged in opposed grates. One of the grates is movable by a hydraulic cylinder toward the other grate which is fixed so that fibrous waste material between the two grates is dewatered. The drainage grooves are then relieved rearwardly and the dewatered waste material is subsequently ejected downwardly at right angles to such horizontal drainage grooves in the grates.
Other apparatuses having drain holes for allowing extracted liquids to leave a mass of compressed materials are disclosed in U.S. Pat. Nos. 2,984,172; 2,711,642; 2,427,446; 1,980,000; 1,553,310; 1,231,929; and 734,591.